It is common in a prosthetic implant, specifically in the femoral portion of a knee joint prosthesis, to provide the option to the surgeon of connecting attachments such as augmentation blocks to the implant. A wide variety of attachment mechanisms and methods are known in the industry for connecting such attachments. One method is to provide a bore for accommodation of a peg carried by the augment. The bore can be formed with threads to accommodate a screw securing the augment and implant together.
It is common for a femoral portion of a knee joint prosthesis to include at least the posterior condyle having an interior surface. The general U-shape of the femoral knee prosthesis forms a limited area between the interior surfaces of the condyles and the anterior wall of the prosthesis. Due to this limited space, it is difficult to properly position automated machining equipment to drill a blind bore into the posterior condylar wall. Providing threads within this bore is also very difficult.